Last night was a time for new life on the reef, as clouds of plankton, brine shrimp and fish eggs rained down in front of the viewports all evening. The microscopic creatures were fascinating. Tiny shapes of shrimp, guppies, and crabs floated and lightly oscillated with the waves above. Occasionally a small jelly fish would join the cloud, or a fish would swim by with its mouth opened. In the morning, Mark told us that the orange cup corals had spawned also. The habitat is covered with an orange coating that looks like a dry sponge. At night, however, it comes alive in stalks of orange feathers of coral that coat the habitat like a cushion.

The aquanauts took advantage of an extra hour of sleep and then got ready for their last dive of the mission. For K2 and Drew, it was also the longest at four hours. The dive started a little late because of helmet communications problems, but the divers made up the time. The first half of the dive consisted of the Exploration Planning and Operations Center (ExPOC) giving directions to the divers to find a simulated cargo ship that had crashed on the moon. The simulated cargo ships were actually two transponders that had been placed the day before. The divers tried two of the moon configurations of the potable life support system (PLSS) mockup suit during the exercise, and rated their performance during each excursion. A simple exercise like falling to your knees once can tell you one thing about a suit, but hiking around in it for an hour, dashing back and forth to tend wayward umbilicals, and using it while your mind is on something else can tell you something completely different. Although it was nowhere close to the sheer strength challenge of the Mars suit, exercising in the moon suit took a bit of effort and stamina.

The second part of the EVA (or extravehicular activity) consisted of repeating the task loop while weighted in the MK12 coverall suits. It was good not to be encumbered with a shoulder-mounted weight belt, but both divers were pretty spent by the time they completed the course six times. In general, all tasks except shoveling were easier with lighter weight. The final course was done with only ten pounds of weight, and both Drew and K2 took advantage of the weightlessness to try bounding and flying around the work area.

In the afternoon, Karen and Koichi completed the survey part of Scenario 1 on their final dive of the mission. They returned to ten of the reefs that the other team (K2 and Drew) had marked on Mission Day 3, and conducted more descriptive analysis of them, and then mapped most of the rest of the work area.

An important question we face prior to returning to the moon is how to maximize the human and robotic resources we have. We have successfully demonstrated that human operators on Earth can control robots on a distant world with numerous Mars missions. We routinely use robotics on the space shuttle and space station that are controlled by in situ astronauts. And we have the experience of hundreds of suited spacewalks. What we don't have much experience with is optimizing between the three options. Crew time is precious, so it's advantageous to move operations to ground controllers wherever possible. The ground has the time delay to deal with, but they have advantages like being able to work all night long while the crew is sleeping. In short, there is always a tradeoff between the more precious crew time and the (expected) higher efficiency of crew work. How to optimize the split of work between spacewalk work, crew controlled robotics, and ground controlled robotics is an important question that needs to be answered prior to returning to the moon.

The remotely-operated vehicle (ROV) on this NEEMO mission performs the role of the robot. It can be a surface rover, or a free flyer (resembling the end of a robotic arm.) It can be controlled by the control center in Houston, or the in situ crew. As the mission continues, we have been experimenting with all options and documenting lessons learned to help answer the larger question of how best to split work. Following on the work done on NEEMO 9, we have designed exercises to answer these questions on NEEMO 10. Over the course of multiple missions we expect to have a significant database to help drive our lunar operations concepts.

Just as on the International Space Station, future inhabitants of the moon or Mars will need periodic cargo vehicles to resupply them with the essentials they need to live in such a harsh environment (air, water, food, etc.). The cargo vehicle will be targeted to land close (but not too close!) to their base. It's also likely that the cargo vehicle will have a homing beacon. So a task astronauts may one day face will be to follow the homing beacon to their cargo vehicle with fresh supplies.

In the last two days we have exercised all of these concepts with different exercises. The Mission Control Center (MCC) team in Houston did a timed exercise to find out how long it took them to find different markers deployed nearby with the ROV. Later the suited crewmembers performed the same task, and the respective times were logged for comparison. Later the MCC team navigated the ROV around the natural obstacles of the reef to a homing beacon hidden hundreds of feet in the distance. This exercise was repeated with suited crewmembers being vectored by the MCC.

Obviously one of the primary science tasks on the moon or Mars will be collecting rock samples. We envision that the crew will find samples on their excursions, the planetary scientists in the MCC will analyze them remotely, and later send the crew back to those locations that looked most interesting to get more samples. This scenario was exercised today, with a planetary scientist from the Astromaterials Research and Exploration Science (ARES) group at Johnson Space Center playing her role.

Finally, the crew supported a first ever linkup with representatives of the Japan Marine Science and Technology Center (JAMSTEC). This government institution is chartered with many of the same responsibilities as the National Oceanic and Atmospheric Administration (NOAA) in the United States. It was a unique linkup by having representatives of JAMSTEC and NOAA, the Japan Aerospace Exploration Agency (JAXA) and NASA together discussing common goals. Perhaps this will be the first step for more meaningful collaboration and partnerships between the agencies in the future.